Method and device for wrapping multi-sheet printed products

ABSTRACT

A device for wrapping multi-sheet printed products includes a conveyor carrying a multi-sheet printed product, a first rotating drum having a first exterior surface with at least one surface indentation, and a second rotating drum having a second exterior surface, the second roattaing drum interacting with the first rotating drum at a first nip. A first wrapping supply provides first wrapping to the first nip on one side of a multi-sheet printed product and a second wrapping supply provides second wrapping to the first nip on another side of the multi-sheet printed product. A method for wrapping a multi-sheet printed product is aslo provided.

The present invention is directed to a method and device for wrapping multi-sheet printed products, for example wrapping newspapers with plastic for protection.

BACKGROUND

U.S. Pat. No. 5,189,865 describes a method and device for wrapping a multi-sheet printed article, such a bundle of signatures of a newspaper.

SUMMARY OF THE INVENTION

An object of the present invention is to improve the throughput of devices for wrapping multi-sheet printed products.

The present invention provides a device for wrapping multi-sheet printed products comprising:

a conveyor carrying a multi-sheet printed product;

a first rotating drum having a first exterior surface with at least one surface indentation;

a second rotating drum having a second exterior surface, the second roattaing drum interacting with the first rotating drum at a first nip;

a first wrapping supply providing first wrapping to the first nip on one side of a multi-sheet printed product; and

a second wrapping supply providing second wrapping to the first nip on another side of the multi-sheet printed product.

By using rotating drums to wrap the multi-sheet printed products, faster speeds are possible than with reciprocating wrappers.

The second rotating drum may have a second indentation on its outer surface, and the printed product may fit within the first and second indentation as it passes through the nip.

One of the first or second rotating drums may have a knife to cut the wrapping material, and the other drum may have an anvil to interact with the knife.

The first and second rotating drums also may be heated at their exterior surfaces to melt the first and second wrapping together around the printed product.

The first wrapping and second wrapping may be delivered as a continuous film. The wrapping may be made of plastic or thermoplastic material.

The exterior surfaces may be ribbed and interact with each other so as to crimp the first and second wrappings together.

The conveyor may be a gripper conveyor, and the grippers can drop the printed products into the nip.

A sensor can be provided downstream from the nip to check the completed bag formed by the two wrappings encloses a printed product. If so, the full bag may be delivered to a further conveyor. If the bag is empty, the empty bag may be blown away using a blower. The sensor may also check for skewed bags.

The present invention also provides a method for forming bags around multi-sheet printed products comprising the steps of:

delivering a multi-sheet printed product to a nip of two drums between two wrappings passing through the nip;

passing the multi-sheet printed product and two wrappings through the drums; and

sealing the two wrappings around the printed product using the nip so as to form a bag around the multi-sheet printed product.

The method may further include cutting the bag.

The bag may remain open at one or both ends, or may be closed at both ends.

The multi-sheet printed product may enter the nip horizontally, vertically or at any other angle.

The present invention may have particular applicability to wrapping newspapers, leaflets, and jackets or a combination thereof, which form collated packs and can be delivered for example with a gripper conveyor.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is described on the basis of the following figures, as well as their descriptions, in which:

FIG. 1 shows a side view of the embodiment in which a gripper conveyor delivers newspapers to two drums;

FIG. 2 shows a perspective view of the outer surface of the drums;

FIG. 3 shows a schematic cross-sectional view A-A from FIG. 2 of the nip of the drums; and

FIG. 4 shows a schematic view of a wrapped printed product formed by the device of FIGS. 1 to 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 shows a side view of a preferred embodiment in which a gripper conveyor 10 having a plurality of grippers 12 conveys newspapers 14 to a nip area 20 of a first drum 22 and a second drum 24. Each drum 22, 24 in this embodiment has a plurality of indentations 32, 34, respectively, on its exterior surface, as shown more clearly in FIG. 2.

Referring again to FIG. 1, a film of a first wrapping 52 is unrolled from a roll 42 and delivered to the outer surface of drum 22, and a film of a second wrapping 54 is unrolled from a roll 44 and delivered to the outer surface of drum 24. Wrapping 52, 54 may be made for example of plastic or a thermoplastic material. While wrappings 52, 54 are shown here as continuous films, they also might be able to be delivered as individual sheets in some embodiments.

The wrappings 52, 54 are crimped together and heated by crimping surfaces 36, 38 of drums 22, 24 respectively, as shown in FIG. 2. Thus bags are being continuously formed by the drums, and the indentations 32, 34 provide an uncrimped area of the wrappings 52, 54 which forms a pocket in the bag for the newspaper to enter.

A serrated or flat knife 46 interacts with an anvil 48 to cut the bags, so that separated full bags 60 are formed after the nip area 20, as shown in FIG. 1.

A sensor at a chute 80 can determine, for example by using a scale to measure weight. A blower can blow away bags which are not full.

A conveyor 70 can then carry away full bags.

FIG. 3 shows a schematic cross-sectional view A-A from FIG. 2 of the nip of the drums. Crimping surfaces 36, 38 are shown in more detail, and interact so that elevations of one surface mesh with depressions of the other surface. Heating elements 72 may be provided to provide heat to the surfaces 36, 38.

FIG. 4 shows a schematic view of a wrapped printed product 60. The sealed printed product causes a raised or bulging area 62 on the wrapping material. A printed area 64 may be provided on the wrapping material. For example the wrappings may be preprinted.

Rotating drum as defined herein may be cylindrical or oblong, for example through the use of a rotating belt. 

1. A device for wrapping multi-sheet printed products comprising: a conveyor carrying a multi-sheet printed product; a first rotating drum having a first exterior surface with at least one surface indentation; a second rotating drum having a second exterior surface, the second roattaing drum interacting with the first rotating drum at a nip; a first wrapping supply providing first wrapping to the nip on one side of a multi-sheet printed product; and a second wrapping supply providing second wrapping to the nip on another side of the multi-sheet printed product.
 2. The device as recited in claim 1 wherein the second exterior surface has a second indentation, the first and second indentations lining up in the nip.
 3. The device as recited in claim 1 wherein one of the first or second rotating drums has a knife to cut the first and second wrappings, and the other of the first and second rotating drums has an anvil interacting with the knife.
 4. The device as recited in claim 1 wherein at least one of the first and second rotating drums are heated to melt the first and second wrapping together around the printed product.
 5. The device as recited in claim 1 wherein the first wrapping and second wrapping are continuous films.
 6. The device as recited in claim 1 wherein the first and second exterior surfaces crimp the first and second wrappings together.
 7. The device as recited in claim 1 wherein the conveyor is a gripper conveyor
 8. The device as recited in claim 7 wherein the gripper conveyor has grippers releasing the printed products above the nip.
 9. The device as recited in claim 1 further comprising a full bag sensor downstream from the nip.
 10. A method for forming bags around multi-sheet printed products comprising the steps of: delivering a multi-sheet printed product to a nip of two drums between two wrappings passing through the nip; passing the multi-sheet printed product and two wrappings through the drum; and sealing the two wrappings around the printed product using the nip so as to form a bag around the multi-sheet printed product.
 11. The method as recited in claim 10 further comprising cutting the bag.
 12. The method as recited in claim 10 wherein the bag is closed at both ends.
 13. The method as recited in claim 10 wherein the multi-sheet product is a newspaper. 